Assistance with updgrade - Wells Gardner 19K4615 monitor

[JeffSD]

Hoping someone can assist me with an issue getting my upgraded PC and video card to work with my Wells Gardner 19K4615 monitor.  I'm attempting to get more speed so that I can run other than very basic games, but have been unable to get the video working with any of the new hardware I have.

Current setup is very old HP Pavilion (circa 1995) with standard VGA on the motherboard running DMAME with AdvanceMENU frontend.  Runs (slow) and video is fine.  Connection from the PC VGA out to the monitor is straight RGB and h-sync/v-sync tied together - no voltage converter.  This is all in a jamma cabinet (Guardians of the Hood) and the monitor must have been in a Super Cobra cabinet for a long time because I can still see the burn in on the screen for that game.  For the controls, I have a keywiz (? I think). Anyway...

Following are the video settings from Advmame.rc for my working (but slow) configuration;
=====
display_mode auto
display_adjust generate_yclock
device_video_clock 5-100 / 15.75 / 60
device_video_format 15750 0.64 0.16 0.08 0.12 0.874046 0.0534351 0.0114504 0.0610687
device_video_modeline ntsc_vga_text40_8x8 12.5872 320 510 570 800 200 224 227 262 -hsync –vsync
=====

I've made several attempts to upgrade with different PCs, video cards (Radeon X300 and Radeon 9000) and with several different approaches;
- lincade
- GroovyArcade
- compiled AdvanceMenu on Ubuntu 10.10 using the same video settings shown above
- XP with the Radeon 9000 using Catalyst 6.5 driver and Soft15Khz

Unfortunately, all of these attempts have the same result - no *usable* video.  I can see that the video card is outputting the right frequency because the screen shows something - just scrambled garbage.  I'm wondering if there is something peculiar with this monitor.

Looking for any and all suggestion please.  Let me know what additional information will help diagnose the problem or what tests I can perform.

Thanks in advance for any assistance.

Jeff